In copending application Ser. No. 401,319, there is disclosed a structure for isolating adjacent semiconductor active and/or passive elements by preferential etching of isolating regions in the semiconductor body. By the use of such isolation, a very substantial reduction in size of the individual semiconductor elements and isolating regions can be achieved over conventional isolation means, such as diffusion isolation and/or oxidation isolation. Such a reduction in size can result in an increased yield of semiconductor integrated circuits from a wafer of a given size since the number of spoiled circuits resulting from imperfections in the wafer is reduced as the overall size of the integrated circuit is reduced. Among the factors which contribute to the total area required for an individual element, such as the memory cell of a large scale integrated circuit, are the emitter, base, and collector contact areas, the isolation regions, the passive element regions, such as resistors, and the contact areas for such resistors. Resistors formed by diffusion from the surface of the semiconductor body through mask openings have been preferred for production purposes since the dimensional area of the resistors can be relatively accurately controlled by means of the mask opening and the total value of the resistor can be controlled by control of the duration temperature and impurity content of the diffusing process. However, such resistors generally require a large area because they are of lower resistance material than the epitaxial layer into which they are diffused and, hence, generally require relatively large areas of the surface of the semiconductor body.